This invention relates to a support adapted to support one end of a board, and more specifically to a portable, collapsible support for use in making temporary carpenters' sawhorses, scaffolding and other platforms used in the construction industry.
Conventional trestle structures, typically known as carpenters' sawhorses, have been used in the construction industry not only as a sawhorse but for supporting other structures such as scaffolding and staging. However, the conventional carpenters' sawhorses are bulky, and heavy, and therefore difficult and inconvenient to transport to and from, and store at a construction site. Moreover, the conventional sawhorses are somewhat complex in their structure and costly to manufacture.
Because of the above disadvantages with the conventional sawhorses, tradesmen in the construction industry typically form A-shaped members at the construction site, which, when used in pairs, support a plank-like board or platform. These handmade supports are usually not reusable, and waste valuable construction time and material.
Numerous portable supports have been suggested in the prior art to meet the need for a prefabricated, portable platform support. However, the apparatus disclosed in the prior art is bulky such that a plurality of supports cannot be compactly stacked for shipping, transport or storage. Moreover, many of the portable prior art supports include a complexly designed combination of numerous components which are expensive to manufacture.
Some prior art portable supports are generally A-shaped and provide an opening or socket for receiving a board to be supported. The opening is sized to be substantially equal to the cross-sectional dimensions of the board. The opening formed in this manner prevents use of the supports with boards having different cross-sectional dimensions; requires that the supports be manufactured within fine tolerances, which increases the cost of manufacture; and, makes it difficult and time-consuming for one person to assemble a horse because the board must be first precisely aligned orthogonal with the opening of the support before it can be fitted through the opening.
In using portable supports to form a horse, some provision must be made to avoid relative sliding movement between the board and the support. This relative sliding movement can result in the collapse of the horse. To resist relative sliding movement, the prior art portable supports either depend upon the coefficient of friction of contacting surfaces of the board and the support, upon a portion of the support abutting against preformed notches in a specially prepared board, or upon a set screw or mechanical locking mechanism which attempts to hold the position of the board in the support. However, resistance against the relative sliding movement for most of these prior art supports does not substantially increase as a downwardly applied force on the board is increased.
In view of the above, it is an object of this invention to provide a new and improved prefabricated, portable support which may be readily reused, and, when not in use, compactly stacked with a plurality of supports for transporting between job sites and storage at the job sites.
It is a further object of this invention to provide a portable, prefabricated support that has few components, is simple in design, relatively inexpensive to manufacture and is readily assemblable and disassemblable.
It is a further object of this invention to provide a new and improved prefabricated portable support which, when used in pairs, braces a plank or board; and which prevents relative sliding motion between the board and the support by substantially increasing the resistance against the relative sliding motion as a downwardly applied force exerted on the board is increased.